Lectin‐Based Estimation of Glycated Hemoglobin in Diabetes Mellitus

This study was undertaken to distinguish between normal and diabetic subjects by lectin–glycated hemoglobin interaction. The quantitative precipitin method was performed for the interaction between glucose‐specific lectin Concanavalin A (Con A) and the glucose‐containing RBC‐lysate for the estimation of calculated HbA1c% from a standard curve. The standard curve was prepared by plotting the optical density of the precipitin for the interaction of standard HbA1c concentration with Con A against HbA1c reference standard. The absorbance range of the precipitate was 0.14–0.20 in normal subjects and the corresponding calculated HbA1c% along with plasma glucose (mg/dl) levels was 4.1–5.8% and 82–101 mg/dl respectively. Higher absorbance values, 0.22–0.42, were obtained in diabetic patients when the calculated HbA1c% was 6.3–12.2% and plasma glucose level was 120–292 mg/dl. Almost similar results were observed for HbA1c% (6.1–11.9%) of the same diabetic samples measured by conventional ion‐exchange high performance liquid chromatography (HPLC). Excellent correlation coefficients of the two methods from regression analysis graph for normal ( r = 0.98) and diabetic patients ( r = 0.99) were observed. Furthermore, nondiabetic and diabetic hemoglobin variant subjects showed similar HbA1c% by our lectin‐based assay when compared with standard HPLC method. We conclude that this lectin‐based assay may be adopted to estimate glycated hemoglobin level in differentiating between normal and diabetic patients. This assay offers a good correlation with standard HPLC method. Moreover; the method is convenient, cheap, and needs no sophisticated instruments.